Method and system for secure automatic media dependent interface reconfiguration and repair

ABSTRACT

Aspects of the invention include determining or choosing any usable media pair from all existing media pairs of a first device. Any channel may be selected from all existing channels and the selected channel is chosen so that it is different from a general channel assignment corresponding to the determined usable media pair. The selected channel may be assigned to the media pair. A second device may be notified of the assigned channel which corresponds to the media pair chosen from all the media pairs. The second device may cross-connect a corresponding equivalent channel and media pair. The first and second device may be adapted to negotiate the assignment of the selected channel to any one of the media pairs. Alternatively, a particular channel and media pair assignment may be selected from a plurality of predetermined channel and media pair assignments and utilized by the first and second device.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application makes reference to U.S. patent application Ser. No.10/612,729, Publication No. 2005/0002328, entitled “Method and Systemfor Automatic Media Dependent Interface Reconfiguration and Repair,”which was filed concurrently herewith on Jul. 2, 2003 and incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to communications mediaconfiguration. More specifically, certain embodiments of the inventionrelate to a method and system for secure automatic media dependentinterface (MDI) reconfiguration and repair.

BACKGROUND OF THE INVENTION

The coupling and configuration of two interfaces in a communicationsystem is generally critical to the operation of devices whoseinterfaces are being coupled. In some instances, improper coupling orconfiguration may result in one or more of damaged equipment,malfunctioning equipment and system failure. Particularly in systemswhich lack redundancy, improper coupling or configuration may, incertain instances, render a system or specific sub-system inoperable. Inorder to mitigate the effects of improper coupling and configuration,various techniques and methodologies have been implemented. Automaticmedia dependent interface (MDI) crossover (Auto-MDIX),Ethernet@wirespeed and cable diagnostics, for example, provide ways foreliminating or otherwise mitigating certain effects that result fromimproper coupling or configuration.

In a typical 4-pair conductor or wire system, auto-MDIX may be adaptedto automatically detect the order of media pairs 1 and 2 and in certaininstances, auto-MDIX may reconfigure only certain channels so as toproperly re-assign the transmit/receive media pairs to these channels.Auto-MDIX may also be adapted to reconfigure channel ordering forcertain channels in order to mitigate the effects of improperinterfacing and/or configuration. In 1000 Base-T mode for example,auto-MDIX may reconfigure the operational mode of media pairs 3 and 4 inaccordance with or dependent on the order of media pairs 1 & 2.Auto-MDIX may eliminate a need for crossover cables which may beutilized between hubs and routers, for example. Finally, auto-MDIX maysimplify installation in certain applications since the wiring order ofa cable plant does not have be known.

Notwithstanding, Auto-MDIX is limited to reconfiguring only media pairs1 and 2 and media pairs 3 and 4. In particular, auto-MDIX relies on abasic assumption that media pairs 1 & 2 are wired respectively and mediapairs 3 & 4 are wired respectively. Accordingly, a major drawback withauto-MDIX is that auto-MDIX does not operate on other combinations ofwiring configurations. For example, auto-MDIX does not operate on mediapairs 1 and 3 or media pairs 2 and 4 and as a result, may be able toreconfigure and/or correct an improper installation involving mediapairs 1 and 3 and media pairs 2 and 4. Another disadvantage of auto-MDIXis that it operated on a basic assumption that media pairs 1 and 2 arewired respectively and media pairs 3 & 4 are wired respectively.

On the contrary, Ethernet@wirespeed provides an algorithm that isadapted to detect the conditions on the media and/or the couplinginterface and to select and implement an appropriate methodology formitigating the effects of improper cabling or interfacing. In thisregard, Ethernet@wirespeed may be adapted to automatically down shift orreduce transmission speed whenever optimal transmission cannot bemaintained or supported due to impairments in the channelcharacteristics, which may be caused by improper cabling or interfacing.Ethernet@wirespeed may be particularly useful in cases where channel ormedia characteristics have degraded but the channel or media is stillrequired for providing communication. For example, in 1000 Base-Tapplications, the conditions on the media may deteriorate to a pointwhere 1000 Base-T operational speeds cannot be sustained, but thechannel cannot be taken out of service because it is needed forproviding data communication. As a result, 10/100 Base-T service may beprovided. One drawback with Ethernet@wirespeed is that it does notoperate on a broken or damaged media pair 1 or media pair 2 in a cableplant. Moreover, Ethernet@wirespeed does not have the capability toreconfigure wire pairs in order to utilize other good pairs in the cableplant. For example, in a case where media pair 3 or pair 4 may beunused, Ethernet@wirespeed does not have the capability to reconfiguremedia pair 3 or media pair 4 for communication.

In contrast, cable diagnostics may be adapted to provide informationpertaining to the quality of a cable plant. In this regard, cablediagnostics may detect whether there is, for example, an open, short orproper termination on the cable or media. Cable diagnostics may beadapted to determine, for example, the length of the cable plant ormedia, and provide information regarding a location of an impedancemismatch in the cable plant. Notwithstanding, cable diagnostics does nothave the capability to determine whether the cable plant has beenincorrectly installed. For example, in a case where media pair 1 andmedia pair 3 are swapped but all the termination points are correct,cable diagnostics does not have the capability to detect and report theswapped cable condition. In this case, cable diagnostics will reportthat all is copasetic, even though media pair 1 has been swapped withmedia pair 3.

Various standards such as 10 Base-T, 100 Base-T and 1000 Base-T havebeen developed to provide communications over unshielded twisted pair.For example, 1000 Base-T was developed to provide data communication atspeeds of the order of 1 Gigabits per second (Gbps) over category-5(CAT-5) unshielded twisted pair (UTP) wire or cable. The 1000 Base-Tstandard defines a five (5) level pulse amplitude modulated signal thatmay be transmitted the CAT-5 wiring. In this regard, a 1000 Base-Ttransceiver may be adapted to transmit data at a rate of 125 megasymbolsover each pairs in a 4 media pair in a CAT-5 wire or cable. Since each125 megasymbol carries 250 megabits per second, the effective rate overfour (4) media pairs is one gigabit per second.

To mitigate the effects of interference such as near-end crosstalk,far-end crosstalk, echo and attenuation resulting from use of theunshielded twisted pair, a 1000 Base-T transceiver may include an analogfront end (AFE). The analog front end may include, but is not limitedto, analog-to-digital converters (ADCs), digital-to-analog converters(DACs) and amplifiers. These devices that may be required to implementthe analog front end may require additional chip area, which increasesthe size of the transceiver chip.

FIG. 1 is a block diagram of a conventional auto-MDIX system, whichutilizes four (4) media pairs. Referring to FIG. 1, there is shown afirst AFE 102 which is a 10/100/1000 Base-T AFE, a second AFE 104 whichis a 10/100/1000 Base-T AFE, a third AFE 106 which is a 1000 Base-T AFE,a fourth AFE 108 which is a 1000 Base-T AFE, a first auto-MDIXcontroller 110 and a second auto-MDIX controller 112. The first AFE 102may be coupled to a first media pair and the second AFE 104 may becoupled to a second media pair. The third AFE 106 may be coupled to athird media pair and the fourth AFE 108 may be coupled to a fourth mediapair. The first auto-MDIX controller 110 is coupled to a channel Atransmit/receive data signal and a channel B transmit/receive datasignal. The second auto-MDIX controller 112 is coupled to a channel Ctransmit/receive data signal and a channel D transmit/receive datasignal. Although AFEs 106, 108 are represented as 1000 Base-T AFEs, theymay be configured to provide additional 10/100 Base-T functionality.

Notwithstanding, in the auto-MDIX configuration of FIG. 1, the firstcontroller 110 operates independent of the second controller 112. Thefirst controller 110 may only control the coupling or cross-connect ofchannel A or channel B to any of only the first media pair or the secondmedia pair. Similarly, the second controller may only control thecoupling or cross-connect of channel C or channel D to any of only thefirst media pair or the second media pair. Accordingly, the firstcontroller 110 cannot cross-connect channel A or channel B to any of thethird media pair or the fourth media pair and the second controller 112cannot cross connect channel C or channel D to any of the first mediapair or the second media pair.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

Certain embodiments of the invention may include a method and system forproviding and configuring secure communication links. The method forproviding and configuring secure communication links may includedetermining or choosing any one usable media pair from all existingmedia pairs of a first device. Any one channel may be selected from allexisting channels so that the selected channel is different from ageneral channel assignment corresponding to the determined usable mediapair. The selected channel may be assigned to the media pair. A seconddevice may be notified of the assigned channel which corresponds to themedia pair chosen from all the media pairs. The second device maycross-connect a corresponding channel and media pair which is equivalentto the selected channel assigned to the media pair. The method may alsoinclude negotiating the assignment of the selected channel to any one ofthe media pairs. A particular one of the channel and media pairassignments may be selected from a plurality of predetermined channeland media pair assignments.

A first combination of the previously assigned channel and media pairmay be designated as a communication channel and media pair. Similarly,a second combination of the channel and the previously assigned mediapair may be designated as a communication channel and media pair.Communication traffic may be securely transferred via the communicationchannel and media pair. Similarly, control information may be securelytransferred via the control channel and media pair and/or thecommunication channel and media pair. A second device may be adapted tomonitor the communication channel and media pair and/or the controlchannel and media pair in order to determine the selected channel andmedia pair assignment utilized by the first device. The controlinformation may include, but is not limited to, authenticationinformation, encryption information, channel setup information, linkprovisioning and/or link maintenance information.

Another embodiment of the invention may provide, a machine-readablestorage, having stored thereon a computer program having at least onecode section for providing and configuring secure communication links.The at least one code section may be executable by a machine, therebycausing the machine to perform the steps for providing and configuringsecure communication links.

The invention may also provide a system for configuring communicationlinks. The system may include at least one controller which may beadapted to determine a usable media pair from all existing media pairs.The controller may be adapted to select any channel from all existingchannels. The controller may select the channel so that it is differentfrom a general channel assignment corresponding to the determined usablemedia pair. At least one selector may be adapted to select a channelthat may be assigned to the media pair. The controller may be configuredto notify a second device of the assigned channel which corresponds tothe media pair chosen from all the media pairs. A second controllerand/or selector associated with the second device may cross-connect acorresponding channel and media pair which is equivalent to the selectedchannel assigned to the media pair. The controllers associated with eachof the first and second devices may also negotiate the assignment of theselected channel to any one of the media pairs. The selector may selecta particular one of the channel and media pair assignments which may beselected from a plurality of predetermined channel and media pairassignments.

A first combination of the previously assigned channel and media pairmay be designated as a communication channel and media pair. Similarly,a second combination of the channel and the previously assigned mediapair may be designated as a communication channel and media pair. Thecontroller associated with the first device may be configured tosecurely transfer communication traffic via the communication channeland media pair. Similarly, the controller may be adapted to securelytransfer control information via the control channel and media pair orthe communication channel and media pair. The second controllerassociated with the second device may monitor the communication channeland media pair and/or the control channel and media pair in order todetermine the selected channel and media pair assignment utilized by thefirst device. The control information may include, but is not limitedto, authentication information, encryption information, channel setupinformation, link provisioning and link maintenance information.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional auto-MDIX system, whichutilizes four (4) media pairs.

FIG. 2 is a block diagram of an automatic MDI reconfigure and repairsystem, which utilizes four (4) media pairs in accordance with anembodiment of the invention.

FIG. 3 is a block diagram of an automatic media dependent interfacereconfigure and repair system, which may provide full Gigabit four (4)media pairs auto-MDIX in accordance with an embodiment of the invention.

FIG. 4 is a block diagram of an automatic media dependent interfacereconfigure and repair system, which may provide flip port assignment inaccordance with an embodiment of the invention.

FIG. 5 is an exemplary system for providing and configuringcommunication links in accordance with an embodiment of the invention.

FIG. 6 is a block diagram of an exemplary scrambled channel and mediapair assignment for a secure automatic MDI reconfigure and repair systemin accordance with an embodiment of the invention.

FIG. 7 is a block diagram of another exemplary assignment for a secureautomatic media dependent interface reconfigure and repair system inaccordance with an embodiment of the invention.

FIG. 8 is a block diagram of an exemplary control and data channel andmedia pair assignment for a secure automatic MDI reconfigure and repairsystem in accordance with an embodiment of the invention.

FIG. 9 is a block diagram of an exemplary control and data channel andmedia pair assignment for a more secure automatic MDI reconfigure andrepair system in accordance with an embodiment of the invention.

FIG. 10 is a block diagram of an exemplary end-to-end automatic MDIreconfigure and repair system in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the invention may include a method and system for providingand configuring secure communication links. The method may includedetermining or choosing any usable media pair from all existing mediapairs of a first device. Any channel may be selected from all existingchannels and the selected channel is chosen so that it is different froma general channel assignment corresponding to the determined usablemedia pair. The selected channel may be assigned to the media pair. Asecond device may be notified of the assigned channel which correspondsto the media pair chosen from all the media pairs. The second device maycross-connect a corresponding channel and media pair which is equivalentto the selected channel assigned to the media pair for the first device.The first and second device may be adapted to negotiate the assignmentof the selected channel to any one of the media pairs. Alternatively, aparticular channel and media pair assignment may be selected from aplurality of predetermined channel and media pair assignments andutilized by the first and second device.

A first combination of the previously assigned channel and media pairmay be designated as a communication channel and media pair. Similarly,a second combination of the channel and the previously assigned mediapair may be designated as a communication channel and media pair.Communication traffic may be securely transferred via the communicationchannel and media pair. Similarly, control information may be securelytransferred via the control channel and media pair and/or thecommunication channel and media pair. A second device may be adapted tomonitor the communication channel and media pair and/or the controlchannel and media pair in order to determine the selected channel andmedia pair assignment utilized by the first device. The controlinformation may include, but is not limited to, authenticationinformation, encryption information, channel setup information, linkprovisioning and/or link maintenance information.

Further aspects of the invention provide a method and system forautomatic media dependent interface (MDI) reconfiguration and repair(AMRR) which may be used to provide and configure communication links. Amethod for providing and configuring communication links may includedetermining a usable media pair from all existing media pairs andselecting any one channel from all existing channels. The selectedchannel may be assigned to any one of the media pairs. Any one or anycombination of media pairs may be monitored in order to detect theexistence of a communication signal on any of the media pairs. Some orall of the existing media pairs may be monitored to determine which ofthe media pair may be capable of facilitating communication at a maximumcommunication speed and if not, at a reduced speed. Any selected channelmay be cross-connected to any one of the existing media pairs, which maybe capable of facilitating communication at the maximum or reducedcommunication speed

In another embodiment of the invention any channel and media pairassignment of a previously defined general channel and media pairconfiguration, which defines channel and media pair assignments for atleast a portion of all the existing media pairs, may be flipped orotherwise rearranged or re-assigned. Subsequent to flipping, the flippedchannel and media pair assignment may be defined as a default channeland media pair configuration. In another aspect of the invention, astatus of at least one of the existing media pairs and/or one of theexisting channels may be defined. The status of the existing media pairsand/or the existing channels may be stored in one or more registers.

In one embodiment of the invention, automatic MDI reconfigure and repairmay be adapted to detect at least one available and/or usable mediapair, determine proper channel assignments for each of a plurality mediapairs and automatically assign any of a plurality of channels to theavailable or usable media pair. In assigning the channel to the mediapairs, automatic MDI reconfigure and repair may be adapted to assign anychannel to any available or usable media pairs. Automatic MDIreconfigure and repair may be adapted to monitor, detect andautomatically reconfigure available or usable media pairs to provideoptimal communication. In this regard, automatic media dependentinterface reconfigure and repair may be adapted to select available orusable media pairs so that a maximum throughput or communication speedmay be attained.

FIG. 2 is a block diagram of an automatic MDI reconfigure and repairsystem, which utilizes four (4) media pairs in accordance with anembodiment of the invention. Referring to FIG. 2, there is shown a first10/100/1000 Base-T AFE 202, a second 10/100/1000 Base-T AFE 204, a third10/100/1000 Base-T AFE 206, a fourth 10/100/1000 Base-T AFE 208, asingle controller 210 and a register 212. The first AFE 202 may becoupled to a first media pair and the second AFE 204 may be coupled to asecond media pair. Similarly, the third AFE 206 may be coupled to athird media pair and the fourth AFE 208 may be coupled to a fourth mediapair. The single controller 210 may be coupled to channel A'stransmit/receive data signal, channel B's transmit/receive data signals,channel C's transmit/receive data signals and channel D'stransmit/receive data signals.

In accordance with an embodiment of the invention, the single controller210 may be adapted to cross connect or couple channels A, B, C or D toany of the media pairs 1, 2, 3 or 4. In this regard, channel A datasignals may be coupled to any of media pairs 1, 2, 3 or 4 and channel Bdata signals may be coupled to any of media pairs 1, 2, 3 or 4.Similarly, channel C data signals may be coupled to any of media pairs1, 2, 3 or 4 and channel D data signals may be coupled to any of mediapairs 1, 2, 3 or 4. The controller arrangement of FIG. 2 thereforeprovides independent channel to media pair cross connect for all of thechannels and all of the media pairs.

In another embodiment of the invention, controller 210 may be configuredto set or clear one or more bits in register 212. The bits in theregister 212 may be utilized to indicate a current cross connect statusof the automatic MDI reconfigure and repair system. In this regard ahost processor or controller 210, for example, may be adapted to readappropriate portions of register 212 in order to determine an automaticmedia dependent interface reconfigure and repair connection status.Additionally, one or more bits in the control register may be used tospecify or establish a particular cross connect configuration.Accordingly, an external processor may be adapted to set or clearcertain bits in the register 212 to indicate a desired cross-connectionfor a particular channel and media pair. The controller 212 maysubsequently read the register 212 and configure the desiredcross-connect arrangement. In another aspect of the invention, theautomatic MDI reconfigure and repair system may indicate which of themedia pairs are available and currently active or in use. The automaticMDI reconfigure and repair status may also provide an indication ofwhich channels may be cross-connected or coupled to which of the mediapairs and/or which media pairs are available or unavailable. The statusof each channel, media pair and/or cross-connection may be written tothe register 212 by controller 210.

FIG. 3 is a block diagram of an automatic media dependent interfacereconfigure and repair system, which may provide full Gigabit four (4)media pairs auto-MDIX in accordance with an embodiment of the invention.Referring to FIG. 3, there is shown a first 10/100/1000 Base-T AFE 302,a second 10/100/1000 Base-T AFE 304, a third 10/100/1000 Base-T AFE 306,a fourth 10/100/1000 Base-T AFE 308, a single controller 310 and aregister 312. The configuration of FIG. 3 may be used to enhance theauto-MDIX configuration of FIG. 1 by providing connectivity betweenchannel A data signals and media pair 3 and channel B data signals andmedia pair 4. This may overcome a major drawback of the auto-MDIXconfiguration of FIG. 1 where neither channel A nor B may becross-connected or coupled to media pair 3 or media pair 4.

In accordance with another embodiment of the invention, the controller310 may be adapted to automatically determine the assignment of gigabitchannels to media pairs, for example, when a cabling plant may beincorrectly installed. This may occur with greater frequency than in atwo (2) media pair scenario since the greater number of conductors inthe four (4) media pair case increases the likelihood of incorrectwiring. The automatic MID reconfigure and repair system configuration ofFIG. 3 may provide arbitrary assignment of channel data to any mediapair.

In operation, the automatic MDI reconfigure and repair system may beadapted to monitor link pulses from the auto-MDIX pair and determine anyexisting channel A and channel B assignments. The automatic MDIreconfigure and repair system may be adapted to auto-negotiate anddetermine the appropriate channel C and channel D assignments. In oneaspect of the invention, the automatic MDI reconfigure and repair systemmay be adapted to utilize a trial-error method to determine theappropriate channel assignments. Notwithstanding, a status of thechannel assignments for channels A, B, C and D may be denoted inregister 312. Accordingly, a processor such as a host processor and/orcontroller 312 may be adapted to read the register 312 to determine thestatus of the channel assignments.

In another aspect of the invention, a channel assignment/wiring orderdiagnostics may be provided. The channel assignment/wiring orderdiagnostics may be adapted to determine a status of each of the channelsA, B, C, and D and a status of the media pairs 1, 2, 3 and 4. In thisregard, controller 310 may determine the status of the channels and/orthe media pairs and correspondingly update register 312 by settingand/or clearing corresponding bits in the status register. The register310 may subsequently be read to determine the status of the channelsand/or the media pairs. The channel assignment/wiring order diagnosticsmay be executed on a continuous basis or it may be executed at aspecified interval. Notwithstanding, a current channel, media pairand/or cross connect status may be provided by the channelassignment/wiring order diagnostics.

FIG. 4 is a block diagram of an automatic media dependent interfacereconfigure and repair system, which may provide flip port assignment inaccordance with an embodiment of the invention. Referring to FIG. 4,there is shown a first 10/100/1000 Base-T AFE 402, a second 10/100/1000Base-T AFE 404, a third 10/100/1000 Base-T AFE 406, a fourth 10/100/1000Base-T AFE 408, a single controller 410 and a register 412.

In general, channel A may be assigned to media pair 1, channel 2 may beassigned to media pair 2, channel 3 may be assigned to media pair 3 andchannel 4 may be assigned to media port 4. In accordance with anembodiment of the invention, controller 410 or an external processor maybe adapted to configure register 412 to establish a default assignmentfor each of the channels and/or the media pairs. In this regard, thegeneral assignment of the channels to media pairs may be flipped tocreate a default channel and media pair assignment. Accordingly afterflipping the channels/media pairs, channel A may be assigned to mediapair 4, channel 2 may be assigned to media pair 3, channel 3 may beassigned to media pair 2 and channel 4 may be assigned to media port 1.In this case, the channel and media pairs may be flipped with respect tothe general channel and media pair assignment. Notwithstanding, theinvention is not limited in this regard and other default channel andmedia pair assignments other than the general channel and media pairassignment may be similarly defined.

In accordance with an embodiment of the invention, the flip portassignment provided by the automatic MDI reconfigure and repair systemmay allow a single die or package to be used in legacy trace ordering ofmedia pairs. In this regard, a single die or chip may be created for useby a plurality of customers, some of which may desire their own traceordering on their printed circuit board (PCB). For example, the flipport assignment provided by the automatic MDI reconfigure and repairsystem may permit a single die or package to be utilized by a firstcustomer requiring inline ordering and a second customer requiringmirror ordering. Moreover, flip port assignment may provide greaterflexibility in the utilization of magnetics and connectors such as RJ45,without having to re-engineer and/or make significant board changes. Forexample, a customer may chose to place channel A on the right side ofPCB and channel D on the left side of a PCB layout and/or package.Finally, the flip port assignment provided by the automatic MDIreconfigure and repair system in accordance with an embodiment of theinvention may permit tapeout of a single die that can be used in die-upor die-down applications. This may be particularly important in, forexample, flip-chip designs where package substrate cannot be customizedto accommodate customer needs.

FIG. 5 is an exemplary system for providing and configuringcommunication links in accordance with an embodiment of the invention.Referring to FIG. 5, there is shown a controller block 502 and aregister block 510. The controller block 502 may include a selectorblock 504, a detector block 508 and a monitor block 506. The selectorblock 504 may be a multiplexer that may be coupled to one or more mediawhich may bear channels A, B, C and D. The selector block 504 may alsobe coupled to one or more media which may bear media pairs, namely mediapairs 1, 2, 3 and 4. In this regard, there are four media pair shown.Notwithstanding, the invention is not so limited and othercorrespondingly more channels and/or media pairs may be handled bycontroller block 502 of the system. Although the selector block 504,monitor block 508 and detector block 506 are shown within controllerblock 502, the invention is not so limited and other arrangements may bepossible. For example, any one or more of the selector block 504,monitor block 508 and detector block 506 may be located external to thecontroller block 502.

The controller block 502 may be adapted to determine a usable media pairfrom all of the existing media pairs. The selector block 504 mayfacilitate the selection of any channel from all of the existingchannels and the controller block 502 may assign the selected channel toany one of the selected media pairs. The controller block 502 may alsobe configured to determine at least one usable media pair from all ofthe existing media pairs. The detector block 506 may detect whether acommunication signal is present on any one of the usable media pairs,namely media pairs 1, 2, 3, and 4. In this regard the detector block 506may contain suitable logic and/or circuitry to detect pulses on any ofthe media pairs.

In another aspect of the invention, the controller block 502 maydetermine which one of the existing media pairs may be capable offacilitating communication at a maximum or specified communicationspeed. The selector block 504 may subsequently cross-connect theselected channel to the existing media pair which is capable offacilitating communication at the maximum communication speed.Similarly, the controller block 502 may also determine which one of theexisting media pairs may be capable of operating at a reducedcommunication speed relative to the maximum communication speed. Theselector block 504 may subsequently cross-connect the selected channelto the existing media pair which is capable of operating at the reducedcommunication speed. The selector block 504 may also be configured toflip any channel and media pair assignment of a previously definedgeneral channel and media pair configuration, which defines channel andmedia pair assignments for at least a portion of the existing mediapairs. The controller block 502 may then define the flipped channel andmedia pair assignment as a default channel and media pair configuration.

The controller block 502 may be adapted to identify a status of at leastone of the existing media pairs, at least one of the existing channelsand at least one channel and media pair cross-connection. One or moreregisters in the register block 510 may store the identified status inone or more bit locations. Appropriate bit locations in at least oneregister in the register block 510 may be written to reflect changes toa media pair, a channel and/or a cross-connection. Similarly,appropriate bit locations in a register block 510 may be read todetermine the status of a media pair, a channel and/or across-connection.

U.S. patent application Ser. No. 10/612,729 entitled “method and systemfor secure automatic media dependent interface (MDI) reconfiguration andrepair” provides a description of link configuration in accordance withvarious aspects of the invention, and is incorporated herein byreference in its entirety.

Generally, in a normal operational mode, channel 1 may be coupled orcross-connected to media pair 1, channel 2 may be coupled orcross-connected to media pair 2, channel 3 may be coupled orcross-connected to media pair 3 and channel 4 may be coupled orcross-connected to media pair 4. Accordingly, knowing that a firstdevice utilizes the general channel and media pair assignments, a seconddevice may replicate the general channel and media pair assignment inorder to communicate with the first device. The invention provides amethod and system for minimizing the chances of replicating channel andmedia pair assignments so that a second device may communicate with afirst device. Consequently, a more secure communication link may beprovided between the first and the second devices.

In accordance with an embodiment of the invention, the cross-connectionor coupling between any of the channels and the media pairs may berandomly arranged or scrambled to provide a secure high-speedcommunication between two (2) devices. During scrambling, a firstcontroller adapted to control at least one of a first set of channel andmedia pairs associated with a first device may automatically negotiatewith a second controller adapted to control at least one of a second setof channel and media pairs associated with a second device. In thisregard, upon completion of the negotiation process, each of the channeland media pair assignments controlled by the first device's controllerwill be equivalent to channel and media pair assignments controlled bythe second controller.

FIG. 6 is a block diagram of an exemplary scrambled channel and mediapair assignment for a secure automatic MDI reconfigure and repair systemin accordance with an embodiment of the invention. Referring to FIG. 6,there is shown a first 10/100/1000 Base-T AFE 602, a second 10/100/1000Base-T AFE 604, a third 10/100/1000 Base-T AFE 606, a fourth 10/100/1000Base-T AFE 608, a single controller 610 and a register 612. In FIG. 6,the exemplary scrambled channel and media pair assignment shows channelB cross-connected to media pair 4, and channel D cross-connected tomedia pair 2. However, channel A is cross-connected to media pair 1 andchannel C is cross connected to media pair 3, which is characteristic ofthe general channel and media pair assignment or configuration.

FIG. 7 is a block diagram of another exemplary assignment for a secureautomatic media dependent interface reconfigure and repair system inaccordance with an embodiment of the invention. Referring to FIG. 7,there is shown a first 10/100/1000 Base-T AFE 702, a second 10/100/1000Base-T AFE 704, a third 10/100/1000 Base-T AFE 706, a fourth 10/100/1000Base-T AFE 708, a single controller 710 and a register 712. In FIG. 7,the exemplary scrambled channel and media pair assignment shows channelA cross-connected to media pair 4, and channel D cross-connected tomedia pair 1. However, channel B is cross-connected to media pair 2 andchannel C is cross connected to media 3, which is characteristic of thegeneral channel and media pair configuration. Other scrambled channeland media pair assignments are also possible.

In an alternate embodiment of the invention, a plurality of channel andmedia pair assignments may be predefined. The first device may selectone of the plurality of channel and media pair assignments andcross-connect corresponding channels and media pairs as per thepredefined assignment. A second device wanting to communicate with thefirst device may scan through each of the predefined assignments untilit determines that a particular channel and media pair assignments areconsistent with the channel and media pair assignment of the firstdevice. The second device may then cross-connect one or morecorresponding channels and media pair assignments consistent with one ormore determined channels and media pair assignments. The first and thesecond device may then communicate using one or more correspondingcross-connected channels and media pair assignments.

The predefined channel assignments may be stored in one or moreregisters that may be accessible by a controller, which may beconfigured to cross-connect or otherwise couple one or more channel andmedia pair assignments. Accordingly, the first device may have anassociated register that may be adapted to store information related tothe each of the pre-defined assignments and the second device may havean associated register that may be adapted to store information relatedto similar pre-defined assignments. Upon initiation of a communicationsession, for example, each controller may retrieve corresponding channeland media pair assignments information from its associated register.

The following is a table illustrating exemplary predefined channel andmedia pair assignment, which may be stored in a memory or a register.

Ch A Ch B Ch C Ch D Assignment 1 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment2 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 3 Pr 1 x Pr 2 x Pr 3 x Pr 4 xAssignment 4 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 5 Pr 1 x Pr 2 x Pr 3x Pr 4 x Assignment 6 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 7 Pr 1 x Pr2 x Pr 3 x Pr 4 x Assignment 8 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 9Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 10 Pr 1 x Pr 2 x Pr 3 x Pr 4 xAssignment 11 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 12 Pr 1 x Pr 2 x Pr3 x Pr 4 x Assignment 13 Pr 1 x Pr 2 x Pr 3 x Pr 4 x Assignment 14 Pr 1x Pr 2 x Pr 3 x Pr 4 x Assignment 15 Pr 1 x Pr 2 x Pr 3 x Pr 4 x

Referring to the exemplary assignments in the table, assignment 1 may bethe general assignment. In operation, during scrambling, any one of thepredefined assignments 2-15 may be selected from the memory and theappropriate the channel and media pairs may be cross-connected. Forexample, in assignment 14, channel A may be cross-connected to mediapair 4, channel B may be cross-connected to media pair 2, channel C maybe cross-connected to media pair 3 and finally, channel D may becross-connected to media pair 1. The channel and media pair assignmentsmay be stored in memory as a lookup table.

In an alternate embodiment of the invention, various channel and mediapairs may be designated to be utilized as data communication channel andmedia pairs and others may be designated to be utilized as controlchannel and media pairs. In this regard, the communication channel andmedia pairs may transport communication traffic while the controlchannel and media pairs may transport control information. In one aspectof the invention, at least one data communication channel and media pairmay be selected and at least one control channel and media pair may beselected in order to facilitate communication between a first and asecond device.

FIG. 8 is a block diagram of an exemplary control and data channel andmedia pair assignment for a secure automatic MDI reconfigure and repairsystem in accordance with an embodiment of the invention. Referring toFIG. 8, there is shown a first 10/100/1000 Base-T AFE 802, a second10/100/1000 Base-T AFE 804, a third 10/100/1000 Base-T AFE 806, a fourth10/100/1000 Base-T AFE 808, a single controller 810 and a register 812.In FIG. 8, the exemplary control and data channel and media pairassignment illustrates channel A cross-connected to media pair 2, andchannel B cross-connected to media pair 1. Furthermore, channel C iscross-connected to media pair 3 and channel D is cross connected tomedia 4 as in the general channel and media pair configuration. Thechannel A/media pair 2 and channel B/media pair 1 cross-connections maybe designated as the communication channel and media pair assignment andthe channel C/media pair 3 and channel D/media pair 4 cross-connectionsmay be designated as the control channel and media pair assignments.Alternatively, the channel A/media pair 2 and channel B/media pair 1cross-connections may be designated as the control channel and mediapair assignment and the channel C/media pair 3 and channel D/media pair4 cross-connections may be designated as the communication channel andmedia pair assignments.

During initiation of a communication session, for example, between afirst device and a second device, the control channel and media pairsmay be utilized to securely transfer control information that may berequired to establish and/or otherwise facilitate communication via theselected communication channel and media pair. Exemplary controlinformation that may be transferred via the control channel and mediapair may include, but is not limited to, authentication information,encryption information and channel setup parameters such ascommunication speed and protocol specific information. In one aspect ofthe invention, link specific information, for example, may betransferred from a first device to a second device via the controlchannel and media pair. In this regard, a particular control channel andmedia pair may be assigned as a default control channel and media pairthat may be monitored by a second device. The first device maycommunicate the control information via this default control channel andmedia pair, where it may be received by the second device.

In another embodiment of the invention, the exemplary control and datachannel and media pair assignment for a secure automatic MDI reconfigureand repair system may be enhanced by securing both the communicationchannel and media pair assignments and the control channel and mediapair assignments. Accordingly, the control channel and media pairassignments may also be scrambled. FIG. 9 is a block diagram of anexemplary control and data channel and media pair assignment for a moresecure automatic MDI reconfigure and repair system in accordance with anembodiment of the invention.

Referring to FIG. 9, there is shown a first 10/100/1000 Base-T AFE 902,a second 10/100/1000 Base-T AFE 904, a third 10/100/1000 Base-T AFE 906,a fourth 10/100/1000 Base-T AFE 908, a single controller 910 and aregister 912. In FIG. 9, the exemplary control and data channel andmedia pair assignment illustrates channel A cross-connected to mediapair 2 and channel B cross-connected to media pair 1. Furthermore,channel C is cross-connected to media pair 4 and channel D is crossconnected to media 3. The channel A/media pair 2 and channel B/mediapair 1 cross-connections may be designated as the communication channeland media pair assignment and the channel C/media pair 4 and channelD/media pair 3 cross-connections may be designated as the controlchannel and media pair assignments. Alternatively, the channel A/mediapair 2 and channel B/media pair 1 cross-connections may be designated asthe control channel and media pair assignment and the channel C/mediapair 4 and channel D/media pair 3 cross-connections may be designated asthe communication channel and media pair assignments.

FIG. 10 is a block diagram of an exemplary end-to-end automatic MDIreconfigure and repair system in accordance with an embodiment of theinvention. Referring to FIG. 10, there is shown a first device 1000which includes a first 10/100/1000 Base-T AFE 1002, a second 10/100/1000Base-T AFE 1004, a third 10/100/1000 Base-T AFE 1006, a fourth10/100/1000 Base-T AFE 1008, a single controller 1010, register block1012 and a selector block 1014. FIG. 10 also depicts a second device1050 which includes a first 10/100/1000 Base-T AFE 1052, a second10/100/1000 Base-T AFE 1054, a third 10/100/1000 Base-T AFE 1056, afourth 10/100/1000 Base-T AFE 1058, a single controller 1060, a registerblock 1062 and a selector block 1064. Selector block 1014 may be coupledto controller 1010 and selector block 1064 may be coupled to controller1060. Notwithstanding, the invention is not limited in this regard andany of the selector blocks 1014, 1064 may be integrated withincontrollers 1010, 1060 respectively.

For the first device 1000, channel A is cross-connected to media pair 2and channel B is cross-connected to media pair 1. Channel C iscross-connected to media pair 4 and channel D is cross connected tomedia pair 3. For the second device 1050, channel A is alsocross-connected to media pair 2 and channel B is cross-connected tomedia pair 1. Channel C is cross-connected to media pair 4 and channel Dis cross connected to media pair 3.

In operation, controller 1010 of device 1000 may determine a usablemedia pair from all existing media pairs, namely Pr 1, Pr 2, Pr 3 and Pr4. The controller 1010 may be adapted to control selector block 1014 toselect any one channel from all existing channels, namely Ch A, Ch B, ChC and Ch D. The selector block 1014 may select the channel so that it isdifferent from a general channel assignment corresponding to thedetermined usable media pair. A general assignment refers to Ch A beingcross-connected to Pr 1, Ch B being cross-connected to Pr 2, Ch C beingcross-connected to Pr 3 and Ch D being cross-connected to Pr 4. Selectorblock 1014 may be adapted to select a channel that may be assigned to amedia pair. The controller 1010 may be configured to notify the seconddevice 1050 of the assigned channel which corresponds to the media pairchosen from all the media pairs. Controller 1060 of the second device1050 may be adapted to control selector block 1064 so that selector 1064may cross-connect a corresponding channel and media pair, which isequivalent to the selected channel assigned to the media pair. Inanother aspect of the invention, controllers 1010, 1060 may beconfigured to negotiate with each other to determine a mutual assignmentof the selected channel to any one of the media pairs. The selectorblock 1014 for device 1000 may select a particular one of the channeland media pair assignments which may be selected from a plurality ofpredetermined channel and media pair assignments.

In one embodiment of the invention, a first combination of a previouslyassigned channel and media pair may be designated as a communicationchannel and media pair. Similarly, the second combination of the channeland the previously assigned media pair may be designated as acommunication channel and media pair. For example, the channel A/mediapair 2 and channel B/media pair 1 cross-connections for device 1000,collectively referenced as 1016, may be designated as the communicationchannel and media pair assignment. Likewise, the channel C/media pair 4and channel D/media pair 3 cross-connections for device 1000,collectively referenced as 1018, may be designated as the controlchannel and media pair assignments. Additionally, the channel A/mediapair 2 and channel B/media pair 1 cross-connections for device 1050,collectively referenced as 1066, may be designated as the communicationchannel and media pair assignment. Likewise, the channel C/media pair 4and channel D/media pair 3 cross-connections for device 1050,collectively referenced as 1068, may be designated as the controlchannel and media pair assignments.

The controllers 1010, 1060 may be configured to securely transfercommunication traffic via the communication channel and media pair 1016,1066. Similarly, the controllers 1010, 1014 may be adapted to securelytransfer control information via the control channel and media pair1018, 1068, or the communication channel and media pair 1016, 1066. Thecontroller 1060 of device 1050 may be adapted to monitor thecommunication channel and media pair 1016 and/or the control channel andmedia pair 1018 in order to determine the selected channel and mediapair assignment, which may be utilized by device 1000. The controller1010 of device 1000 may also be adapted to monitor the communicationchannel and media pair 1066 and/or the control channel and media pair1068 in order to determine the selected channel and media pairassignment, which may be utilized by device 1050. The controlinformation may include, but is not limited to, authenticationinformation, encryption information, channel setup information, linkprovisioning and link maintenance information.

In one embodiment of the invention, automatic media dependent interfacereconfiguration and repair may be used to enhance the capabilitiesoffered by auto-MDIX. In this regard, automatic media dependentinterface reconfiguration and repair may extend the capabilities ofauto-MDIX by allowing auto-MDIX to provide support for media pairs otherthan media pairs 1 and 2 and media pairs 2 and 4. Accordingly, auto-MDIXusing automatic MDI reconfiguration and repair may permitreconfiguration of media pairs 1 and 3 and media pairs 2 and 4 for useby any of a plurality of channels.

Since multiple transceivers may be implemented on a single PHY device,automatic MDI reconfiguration and repair may be flexibly integratedwithin a PHY device without requiring any additional premium chip realestate. For this reason, automatic MDI reconfiguration and repair may beadapted to utilize existing gigabit architectures without a need forextensive re-engineering which may be costly and time consuming.Additionally, existing PHY transceiver analog front ends (AFEs) utilizedin Gigabit products have the capability to transmit and receive at, forexample, 10 Base-T and 100 Base-TX on all pairs. Moreover, externalcomponents for gigabit products such as termination resistors andmagnetics may be readily capable of transmitting and receiving 10 Base-Tand 100 Base-TX on all media pairs. This makes automatic MDIreconfiguration and repair more desirable that any conventional system.Accordingly, supplemental hardware may be added or existing hardware maybe augmented to arbitrarily switch channel assignments to any pair usingautomatic MDI interface reconfiguration and repair in accordance withthe invention. Automatic MDI reconfiguration and repair may also permitdetection of available media pairs and provide dynamic assignment ofchannels to the available pairs. In this regard, automatic MDIreconfiguration and repair may provide a flexible approach forfacilitating full multiplexing of channel data to available media pairs.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in one computersystem, or in a distributed fashion where different elements are spreadacross several interconnected computer systems. Any kind of computersystem or other apparatus adapted for carrying out the methods describedherein is suited. A typical combination of hardware and software may bea general-purpose computer system with a computer program that, whenbeing loaded and executed, controls the computer system such that itcarries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method for providing and configuring secure Ethernet communicationlinks, the method comprising: determining any one usable media pair fromat least three media pairs of all existing media pairs of a firstdevice, wherein each of said media pairs comprises a twisted pair;selecting any one channel from all existing channels, said selected anyone channel being different from a general channel assignmentcorresponding to said determined any one usable media pair; andassigning said selected any one channel to said any one usable mediapair, wherein said first device communicates using said at least threemedia pairs of said all existing media pairs.
 2. The method according toclaim 1, comprising notifying a second device of said assigned any onechannel which corresponds to said any one media pair.
 3. The methodaccording to claim 2, comprising cross-connecting a correspondingchannel and media pair for said second device, said cross-connectedchannel and media pair being equivalent to said selected any one channelassigned to said any one media pair.
 4. The method according to claim 1,comprising negotiating said assignment of said selected any one channelto said any one media pair.
 5. The method according to claim 1,comprising selecting from a plurality of predetermined channel and mediapair assignments, a particular one of said channel and media pairassignment.
 6. The method according to claim 1, comprising securelytransferring communication traffic via said communication channel andmedia pair.
 7. The method according to claim 6, comprising securelytransferring control information via at least one of said communicationchannel and media pair.
 8. The method according to claim 7, comprising:monitoring at least one of said communication channel and media pair bya second device; and determining said selected any one channel assignedto said any one media pair.
 9. The method according to claim 8, whereinsaid control information is at least one of authentication information,encryption information, channel setup information, and link provisioningand link maintenance information.
 10. A non-transitory machine-readablestorage having stored thereon, a program having at least one codesection for providing and configuring secure Ethernet communicationlinks, the at least one code section being executable by a machine forcausing the machine to perform steps comprising: determining any oneusable media pair from at least three media pairs of all existing mediapairs of a first device, wherein each of said media pairs comprises atwisted pair; selecting any one channel from all existing channels, saidselected any one channel being different from a general channelassignment corresponding to said determined any one usable media pair;and assigning said selected any one channel to said any one usable mediapair, wherein said first device communicates using said at least threemedia pairs of said all existing media pairs.
 11. The machine-readablestorage according to claim 10, wherein said at least one code sectioncomprises code for notifying a second device of said assigned any onechannel which corresponds to said any one media pair.
 12. Themachine-readable storage according to claim 11, wherein said at leastone code section comprises code for cross-connecting a correspondingchannel and media pair for said second device, said cross-connectedchannel and media pair being equivalent to said selected any one channelassigned to said any one media pair.
 13. The machine-readable storageaccording to claim 10, wherein said at least one code section comprisescode for negotiating said assignment of said selected any one channel tosaid any one media pair.
 14. The machine-readable storage according toclaim 10, wherein said at least one code section comprises code forselecting from a plurality of predetermined channel and media pairassignments, a particular one of said channel and media pair assignment.15. The machine-readable storage according to claim 10, wherein said atleast one code section comprises code for securely transferringcommunication traffic via said communication channel and media pair. 16.The machine-readable storage according to claim 15, wherein said atleast one code section comprises code for securely transferring controlinformation via at least one of said communication channel and mediapair.
 17. The machine-readable storage according to claim 16, whereinsaid at least one code section comprises: code for monitoring at leastone of said communication channel and media pair by a second device; andcode for determining said selected any one channel assigned to said anyone media pair.
 18. The machine-readable storage according to claim 17,wherein said control information is at least one of authenticationinformation, encryption information, channel setup information and linkprovisioning and link maintenance information.
 19. A system forproviding and configuring secure Ethernet communication links, thesystem comprising: at least one controller enabled to determine any oneusable media pair from at least three media pairs of all existing mediapairs of a first device, wherein each of said media pairs comprises atwisted pair; at least one selector enabled to select any one channelfrom all existing channels, said selected any one channel beingdifferent from a general channel assignment corresponding to saiddetermined any one usable media pair; and said at least one controllerenabled to assign said selected any one channel to said any one usablemedia pair, wherein said first device communicates using said at leastthree media pairs of said all existing media pairs.
 20. The systemaccording to claim 19, wherein said at least one controller is enabledto notify a second device of said assigned any one channel whichcorresponds to said any one media pair.
 21. The system according toclaim 20, wherein said at least one selector is enabled to cross-connecta corresponding channel and media pair for said second device, saidcross-connected channel and media pair being equivalent to said selectedany one channel assigned to said any one media pair.
 22. The systemaccording to claim 19, wherein said at least one controller is enabledto negotiate said assignment of said selected any one channel to saidany one media pair.
 23. The system according to claim 19, wherein saidat least one selector is enabled to select from a plurality ofpredetermined channel and media pair assignments, a particular one ofsaid channel and media pair assignment.
 24. The system according toclaim 19, wherein said at least one controller is enabled to transfercommunication traffic via said communication channel and media pair. 25.The system according to claim 24, wherein said at least one controlleris enabled to transfer control information via at least one of saidcommunication channel and media pair.
 26. The system according to claim25, wherein at least one controller associated with a second device isenabled to: monitor at least one of said communication channel and mediapair by a second device; and determine said selected any one channelassigned to said any one media pair.
 27. The system according to claim26, wherein said control information is at least one of authenticationinformation, encryption information, channel setup information and linkprovisioning and link maintenance information.
 28. A method forproviding and configuring secure Ethernet communication links, themethod comprising: determining any one usable media pair from allexisting media pairs of a first device, wherein said each of media pairscomprises a twisted pair, and wherein said first device communicateswith at least three media pairs of said all existing media pairs;selecting any one channel from all existing channels, said selected anyone channel being different from a general channel assignmentcorresponding to said determined any one usable media pair; assigningsaid selected any one channel to said any one usable media pair;designating a first combination of said channel assigned to said any oneusable media pair as a communication channel and media pair; anddesignating a second combination of said channel assigned to said anyone usable media pair as a control channel and media pair.
 29. Anon-transitory machine-readable storage having stored thereon, a programhaving at least one code section for providing and configuring secureEthernet communication links, the at least one code section beingexecutable by a machine for causing the machine to perform stepscomprising: determining any one usable media pair from all existingmedia pairs of a first device, wherein each of said media pairscomprises a twisted pair, and wherein said first device communicateswith at least three media pairs of said all existing media pairs;selecting any one channel from all existing channels, said selected anyone channel being different from a general channel assignmentcorresponding to said determined any one usable media pair; assigningsaid selected any one channel to said any one usable media pair;designating a first combination of said channel assigned to said any oneusable media pair as a communication channel and media pair; anddesignating a second combination of said channel assigned to said anyone usable media pair as a control channel and media pair.
 30. A systemfor providing and configuring secure Ethernet communication links, thesystem comprising: at least one controller enabled to determine any oneusable media pair from all existing media pairs of a first device,wherein each of said media pairs comprises a twisted pair, and whereinsaid first device communicates with at least three media pairs of saidall existing media pairs; at least one selector enabled to select anyone channel from all existing channels, said selected any one channelbeing different from a general channel assignment corresponding to saiddetermined any one usable media pair; said at least one controllerenabled to assign said selected any one channel to said any one usablemedia pair; said at least one selector enabled to designate a firstcombination of said channel assigned to said any one usable media pairas a communication channel and media pair; and said at least oneselector enabled to designate a second combination of said channelassigned to said any one usable media pair as a control channel andmedia pair.